Is there a naming convention for network weights for multilayer networks?
When the system grows matrix notation is used, as a=Wx, being a (input to activation function in hidden layer) and x (values from input layer) column vectors, transpose of (a1,a2,...a_m) and (x1,x2,...,x_n), and W a m-by-n matrix of dimensions m rows and n columns. The standard way to denote matrix elements is w(i,j) where "i" is the row number and "j" column number:


(from wiki)

For this reason, the weight that applies to h4 from x3 is element in row 4 column 3 of the matrix W, that is, W(4,3) ( as your teachers advocates but with a sad lack of ability to explain ).

In your example:



Note: things are a few more complex when x1, x2, ... are itself vectors, but final conclusion is the same.

( PS: URGENT to allow latex notation on this stack exchange ! )